Process and apparatus for cracking oil



March 7; 1933.- l N. E. Looms ET AL 1,900,116

PROCESS` AND APPARATUS FOR CRACKING OIL Filed Oct. l, 1926 /7 .BUBBLE TOWER M4 THAN/Ez. E. L OOM/s ALBL'rer h f. ToML/Mo/v Patented Mar. 7,

- NATHANIEL E. LOOMISLOF WESTFIELD,

UNITED ISTATES RATION 0F DELAWARE PATE NT oFFlcEl AND .ALBERZI H. TOMLINSON, 0F ELIZABETH, NEW JERSEY, ASSIGNORS v'.l.0 STANDARD OIL DEVELOPMENT -COIMTPANY, A CORPO- PROCESS AND APPARATUS FOR CRACKING- OIL Application illelctober 1, 1926. ,Serial No. 138,840.

. This invention relates to improvements in processes' and apparatus for cracking hydrocarbon oils having a relatively low boiling point, particularly light gas oil. However, the improvements described are applicable in general to the treatment of oils which are largely in vapor phase at the cracking temperature and pressure. n 4

vThe invention will be fully understood from the following description, taken in connection with the accompanying drawing, -in which the ligure is a diagrammatic side elevation, partly in section, of a preferredform of apparatus.

In the drawing, reference numeral 1 denotes a pipe through which oil is supplied to a -cracking coil 2, arranged in a furnace set-` ting 3. The coil discharges through a pipe 4 into a header or distributing box' mount-l ed about `midway in an elongated vertical soaking drum or digesting chamberor zone 6. vThe drum is insulated by lagging 7 orr in any other suitable way.

. tribution of the stream between Branch pipes 8 and 9vextend respectively.

up and down in the drum 6 from the header 5. The stream of oil vapor divides in the header, part emerging from the uplow pipe 8 and part from the/downflow pipe 9.' The stream may contain some liquid oil, 'but will be mostly oil vapor. The cross'sectional area of each of pipes 8 and 9 is preferably about half that of pipe 4,`so that a fairly even d isthe top and bottom of the drum 'is effected.'

A plurality of drawo connections 10, in .eaehof which a valve ll'iseinstalled, serve for the withdrawal of the contents of the drum'at various heights. The connections 1() discharge into header 12, whichconnects with a pipe 13 fitted with a pressure control valve 14. A bubble 'tower 15, or other vapor separating means, receives the product from pipe 13. The bubble tower has a cooling coil 16 in its top, and in the installation Ashown the oil to be cracked is used as the cooling material, entering the coil 16 throughapipe -17 and emerging into pipe 1 leading to thecracking coil 2. The ltower 15 is provided with bell-cap plates 18 or equivalentaneans. l'Condensate is withdrawn from a pan 1K9 vin 'lecting tank and pump,

and receiver 22. Oil may be supplied for recycling from receiver y22 through valved -pipe 2,3 to the main oil line 1, through a colnot shown), or may be otherwise disposed of. Vapors are taken of fromthe tower through a pipe 24 to a cooler 25, the condensate from this cooler is received in a tank 26, and the 'residual gas,

and vapor are vented through pipe 27. A valved of drum 6, for supplying a temperaturecontrolling fluid thereto, from line 1.

In a typical operation according to the present invention, a continuously flowing stream of light gas oil is highly heated under pressureA in the coil 1, so that it emerges therefrom at a vaporizing 4 ture, which may be about 890 F. under a pressure of 600 lbs. sq. in. The stream of heated oil is discharged into the header 5 and divides as vabove described. The liquid -level in the drum is maintained at a low point by opening the valve 11 in the'lowest connection 10, the other valves 11 being closed.

We have found that inthe vapor phase cracking of light gas oil there are usually heavy liquid components of the oil which are converted into coke'if allowed vto accumulatein the drum. It is therefore .desirable,i.n operations of the type described,

to ,draw oif liquid oil in a manner-to prevent the accumulation of a large body of liquid, and the resulting formation of extensive coke deposits in the drum.

and cracking tempera-j 1 I s pipe 28 opens into the lower portlon L which may be oil predominantly The temperature in the drum may be cond in the drum. `The temperature therein may j be controlled if necessary by introduction of oil through pipe 28, or in othersui-table ways. flhe pressure in the drum may be about 37 54 lbs. sq. inch, the valve 14 being set to open at the desired pressure. Vapors and liquid from the drum pass together through pipe13 Ato the vapor separating and ,condensing system.

.Injection of the stream from the coil into the drum at points adjacent its top and bottom promotes circulation throughout. The

the drum, and of stagnant liquid at itsl botformation of a body of inert gas at the top of tom, are avoided. By maintaining circulation and withdrawing liquid from the drum as described, we are able to secure eiiicient conversion without 'objectionable coke formation. The level at which the liquid is permitted to stand in the drum may be higher when stocks of lovi7 coke-forming character--- istics are being cracked. In such cases withdrawal from an intermediate level is preferred.` The upper connection 10 may be used- `if cracking substantially in liquid phase Lis desired. In general, the relation between the liquid and vapor spaces in the drum is regulated in such cracking without objectionable Jformation of claim all novelty i an elongated vertical soaking drum vinsuing temperature,

coke. Liquid andV vapor are taken off to- -gether from that connection 10 which is selected for withdrawal.

Various changes and alternative proce: dures may be made within the scope of the appended claims, in which itis our intention to inherent in the invention as broadly as'rth'e prior art permits.

We claim: f l

1. Process of cracking hydrocarbon oil in lated againstV yloss of heat, comprising heat-v ing a stream of oil ,to a vaporizing and crack-y stream of hot oil vapor, passing a portion of the stream into an upper part of the drum, passing another portion of the stream into a llower part of the drum,and withdrawing all vaporous and liquid products of conversion together from' an intermediate point in the drum.

2. ln the process of cracking hydrocarbon oilV that includes heating the oil to 4la vaporfzing temperature under pressure in a coil L and passing the hot oil into an elongated vertical soaking drum under conditions to per.-

manner as to secure eicient l. longitudinally spaced points dividing. the resulting spaced relation longitudinally lof the drum,

a header vcommunicatinglwith said outlets and a pipe communicating withk'saidfheader and 'aording the sole outlet for both vapor and liquid products from said drum.- t

4.1The process .of cracking hydrocarbon oil-which' comprises heating the oil to a vaporizingl and cracking temperature, dividof a digestion zone, withdrawing all vaporous and liquid products together from the lower partv of the zone in sufficient vol-- ume toin'aintain a bod carbons in the lower portion only of the zone, and passing another stream of the vapors into the lower portion of the zone below the level of the liquid.

oil that includes heatingthe oil to a vaporizing temperature under pressure in a coil and passing the hot oil into.l an elongated p vertical soaking drum under conditions to permit cracking therein substantially insole consequence of the" contained'heat of the oil, the Vimprovement .that comprises discharging oil vapor from the coil into the drum in directed streams at widely the charge inU the drum is obtained, and

,ing the hot oil vapor into streams, passing l onestream of the .vapors into the vapor space of liquid hydro- 5. In the process of cracking hydrocarbon noY therein, whereby circulation of -I I withdrawing vaporous and liquid products l together from one point in the drum.

6. The process according to claim 5 in which the temperature of the oil in the drum is controlled by the introduction jof controlled amounts of Jfresh feed stock directly into the drum. c

NATHANIEL E. LOOMIS. ALBERT H. .TOMUDINSOIL mit cracking therein substantially in sole consequence of the contained heat of theioil,

the improvement that comprises discharging,y

Jfrom the coil into the drum in oil vapor v longitudinally directed streams at widely spaced points therein, whereby circulation of the charge in the drum is obtained, and withdrawing all vaporous and liquid products together from a low point in the drum.

3. Apparatus for use in crackingl hydrocarbon oil, comprising an elongated vertical soaking drum, a conduit for delivering a stream of hot oil vapor into the drum, a

branched discharge pipe within'the drum communicating with the conduit and adapted .to discharge the oil in oppositely directed streams longitudinally ofthe drum at widely spaced opposite points inthe drum, a plurality of valved outlet pipes arranged in 

